“Krull” (a city-state, actually), started in 1979 – well before the 1983 movie of the same name.

Krull scenarios and game aids may be purchased in PDF format at...

The lands above are the extent of “Krull” circa 1979-81.
(map drawn over time)

Underport: Abyssal Descent, a vintage mega-dungeon.

Originally written incrementally during RPG's early years between mid-1978 and late 1981, the style is swords & sorcery focused on heavy fighting action. Now more than 250 individual, detailed encounters on 9+ dungeon levels plus a small pirate village and 2 underground keeps. 
***Please Note this product was written using an older version of rules based on System Reference Document v.3.5 and will require some creative adjustments to run with the current Advanced Knights of the All Mind rules based on SRD v.5.1.